Disease-Associated Streptococcus pneumoniae Genetic Variation.

Streptococcus pneumoniae is an opportunistic pathogen that causes substantial illness and death among children worldwide. The genetic backgrounds of pneumococci that cause infection versus asymptomatic carriage vary substantially. To determine the evolutionary mechanisms of opportunistic pathogenicity, we conducted a genomic surveillance study in China. We collected 783 S. pneumoniae isolates from infected and asymptomatic children. By using a 2-stage genomewide association study process, we compared genomic differences between infection and carriage isolates to address genomic variation associated with pathogenicity. We identified 8 consensus k-mers associated with adherence, antimicrobial resistance, and immune modulation, which were unevenly distributed in the infection isolates. Classification accuracy of the best k-mer predictor for S. pneumoniae infection was good, giving a simple target for predicting pathogenic isolates. Our findings suggest that S. pneumoniae pathogenicity is complex and multifactorial, and we provide genetic evidence for precise targeted interventions.

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OBJECTIVES: To explore the molecular characteristics of Staphylococcus aureus (S. aureus) in children, and to compare the molecular characteristics of different types of strains (infection and colonization strains) so as to reveal pathogenic molecular markers of S. aureus. METHODS: A cross-sectional study design was used to conduct nasopharyngeal swab sampling from healthy children in the community and clinical samples from infected children in the hospital. Whole genome sequencing was used to detect antibiotic resistance genes and virulence genes. A random forest method to used to screen pathogenic markers. RESULTS: A total of 512 S. aureus strains were detected, including 272 infection strains and 240 colonization strains. For virulence genes, the carrying rates of enterotoxin genes (seb and sep), extracellular enzyme coding genes (splA, splB, splE and edinC), leukocytotoxin genes (lukD, lukE, lukF-PV and lukS-PV) and epidermal exfoliating genes (eta and etb) in infection strains were higher than those in colonization strains. But the carrying rates of enterotoxin genes (sec, sec3, seg, seh, sei, sel, sem, sen, seo and seu) were lower in infection strains than in colonization strains (P<0.05). For antibiotic resistance genes, the carrying rates of lnuA, lnuG, aadD, tetK and dfrG were significantly higher in infection strains than in colonization strains (P<0.05). The accuracy of cross-validation of the random forest model for screening pathogenic markers of S. aureus before and after screening was 69% and 68%, respectively, and the area under the curve was 0.75 and 0.70, respectively. The random forest model finally screened out 16 pathogenic markers (sem, etb, splE, sep, ser, mecA, lnuA, sea, blaZ, cat(pC233), blaTEm-1A, aph(3')-III, ermB, ermA, ant(9)-Ia and ant(6)-Ia). The top five variables in the variable importance ranking were sem (OR=0.40), etb (OR=3.95), splE (OR=1.68), sep (OR=3.97), and ser (OR=1.68). CONCLUSIONS: The random forest model can screen out pathogenic markers of S. aureus and exhibits a superior predictive performance, providing genetic evidence for tracing highly pathogenic S. aureus and conducting precise targeted interventions.

Focused ultrasound: a novel therapy for improving vaginal microecology in patients with high-risk HPV infection.

OBJECTIVES: To investigate changes in vaginal microecology in women with high-risk human papillomavirus (HR-HPV) infection after focused ultrasound (FU) treatment. MATERIALS AND METHODS: We collected vaginal secretions at the time of admission and 3 months after FU treatment from 169 women who received FU treatment for cervical HR-HPV infection between July 2020 and September 2022. Among them, there were 101 patients with cute vaginitis, we also collected their vaginal secretions after one week of drug treatment. These samples were evaluated for vaginal microecology and HPV-DNA examination. RESULTS: Of the 169 patients, 101 (59.7%) suffered from acute vaginitis at the time of admission. After one week of targeted antibiotics drug treatment, there were no pathogens or pus cells on the field of microscopic vision, but there was no significant difference(p > 0.05) in the diversity and density of vaginal flora, the proportion and function of Lactobacillus (H2O2 negative rate) between one week after treatment and at the time of admission. At the time of admission of the 169 patients, the normal flora rate was 40.3%, which increased to 93.5% three months after FU treatment. The differences in vaginal secretion parameters at the time of admission and 3 months after FU treatment were as follows: H2O2 negative rate (37.3% vs. 3.6%), leukocyte esterase positive rate (54.4% vs. 5.9%), sialidase positive rate (38.5% vs. 4.1%), bacterial vaginitis positive rate (55% vs. 4.7%), fungal vaginitis positive rate (44.4% vs. 5.9%), and trichomonal vaginitis positive rate (7.1% vs. 0). The difference was statistically significant (p < 0.01). The pH value and Nagent score at the time of admission were significantly higher than those three months after FU. Three months after FU, the positive rate of HPV was 5.8% in the group of patients with normal vaginal microecology at the time of admission and post-FU; it was 6.7% in the group of patients with abnormal vaginal microecology at the time of admission and normal vaginal microecology post-FU; and it was 100% in the group patients with abnormal vaginal microecology at the time of admission and post-FU. A significant difference was observed among the three groups (p < 0.01). CONCLUSION: FU is an effective treatment for patients with cervical HR-HPV infection. FU does not interfere with the vaginal microecology of HR-HPV positive patients with normal vaginal microecology.FU followed by antibiotic drug therapy for pathogens is beneficial to restore the function of Lactobacillus vaginalis in HR-HPV positive patients with acute vaginitis,so as to improve the vaginal microecology of HR-HPV positive patients with abnormal vaginal microecology.

Risk Identification of Bronchopulmonary Dysplasia in Premature Infants Based on Machine Learning.

Bronchopulmonary dysplasia (BPD) is one of the most common complications in premature infants. This disease is caused by long-time use of supplemental oxygen, which seriously affects the lung function of the child and imposes a heavy burden on the family and society. This research aims to adopt the method of ensemble learning in machine learning, combining the Boruta algorithm and the random forest algorithm to determine the predictors of premature infants with BPD and establish a predictive model to help clinicians to conduct an optimal treatment plan. Data were collected from clinical records of 996 premature infants treated in the neonatology department of Liuzhou Maternal and Child Health Hospital in Western China. In this study, premature infants with congenital anomaly, premature infants who died, and premature infants with incomplete data before the diagnosis of BPD were excluded from the data set. After exclusion, we included 648 premature infants in the study. The Boruta algorithm and 10-fold cross-validation were used for feature selection in this study. Six variables were finally selected from the 26 variables, and the random forest model was established. The area under the curve (AUC) of the model was as high as 0.929 with excellent predictive performance. The use of machine learning methods can help clinicians predict the disease so as to formulate the best treatment plan.

[Clustering and influencing factors of Streptococcus pneumoniae carriage among kindergarten children].

OBJECTIVE: To study the clustering and influencing factors of Streptococcus pneumoniae carriage among kindergarten children, and to provide a scientific basis for the prevention of pneumococcal diseases. METHODS: The multi-stage stratified cluster sampling method was used to collect nasal swabs via the nasal vestibule at both sides from 1 702 kindergarten children in Liuzhou, China. A questionnaire survey was performed on their parents. The chi-square test and the random effects logistic regression analysis were used to analyze data. RESULTS: The carriage rate of Streptococcus pneumoniae was 13.16% (224/1 702) among kindergarten children. The clustering analysis showed that the class-level random effect of Streptococcus pneumoniae carriage was statistically significant (Z=2.07, P=0.038), with an intraclass correlation coefficient of 5.9%. The random effects logistic regression analysis showed that the children aged 5-7 years had a lower risk of Streptococcus pneumoniae carriage than those aged 2-< 5 years (OR=0.55, 95%CI:0.40-0.76, P=0.001), and the children with ≥ 5 family members living together had a higher risk of Streptococcus pneumoniae carriage than those with < 5 family members (OR=1.34, 95%CI:1.01-1.79, P=0.043). CONCLUSIONS: Streptococcus pneumoniae carriage shows a class-level clustering effect, and age and the number of cohabitants are important influencing factors for Streptococcus pneumoniae carriage in children.

Comparison of Three Immunoassay Systems for Determining Serum Anti-Mullerian Hormone.

BACKGROUND: Serum anti-Mullerian hormone (AMH) is a dimeric glycoprotein of the transforming growth factor-ß (TGF-ß) family of growth and serves as a key biomarker of folliculogenesis as well as steroidogenesis within ovaries. Cobas E601, UniCel DxI 800 and iFlash3000 are automated immunoassay systems which are widely used to measure serum AMH levels in the blood. However, the correlations of serum AMH measured by the three automated immunoassay systems are not well recognized, the aim of this study is to compare the performance of the three automated immunoassay systems and record the correlation of serum AMH concentrations. METHODS: Serum AMH concentrations were measured in 100 serum samples using the UniCel DxI 800, Cobas E601, and iFlash 3000 automated immunoassay systems on the same day. Passing-Bablok regression analysis and Bland-Altman plot analysis were used to compare the system methods. The concordance correlation coefficient was analyzed to explain interrater agreement between the three immunoassay systems. RESULTS: Bland-Altman plot showed that the concentrations of AMH measured by UniCel DxI 800 were about 0.15 times higher than that measured using Cobas E601, the concentrations of AMH measured by UniCel DxI 800 were about 0.05 times higher than that measured using iFlash 3000, serum AMH concentrations measured by the iFlash3000 were about 0.19 times higher than that measured using Cobas E601. The concordance correlation coefficient ρc was 0.921, 0.909 and 0.978 for the UniCel DxI 800 versus the Cobas E601, the iFlash 3000 versus the UniCel DxI 800, and the iFlash3000 versus the Cobas E601, respectively. CONCLUSIONS: The three measurement systems have good correlation with each other for determining serum AMH.

Diagnostic Value of Serum DNASE1L3 in Hepatitis B Virus-Related Hepatocellular Carcinoma.

BACKGROUND: Deoxyribonuclease 1-like 3 (DNASE1L3) is an endonuclease associated with many autoimmune diseases and tumors. However, the serum DNASE1L3 level in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) remains unreported. Thus, this study compared the diagnostic value of DNASE1L3 and alpha-feto-protein (AFP) individually and in combination in HBV-related HCC. METHODS: The study population consisted of 88 patients with HBV-related HCC, 80 patients with HBV-related liver cirrhosis (LC) and 88 control subjects. The serum DNASE1L3 levels were measured using an enzyme-linked immunosorbent assay. The serum AFP was also assayed. RESULTS: Our data showed that the serum DNASE1L3 levels were significantly higher in patients with HBV-related HCC than in the healthy controls and patients with LC. When the two biomarkers were analyzed individually, the receiver operating characteristic curve analysis showed that the areas under the curve of DNASE1L3 and AFP were 0.898 and 0.866, respectively. When DNASE1L3 and AFP were combined, the area under the curve was 0.951. The sensitivities of DNASE1L3 and AFP were 72.73% and 74.81%, respectively, and the specificities were 93.18% and 92.05%, respectively, in the diagnosis of HBV-related HCC. The sensitivity of the two combined could be improved to 89.77%. However, no correlation was found between serum DNASE1L3 and AFP in HBV-related HCC patients (r = 0.005, p = 0.734). CONCLUSIONS: Serum DNASE1L3 has high sensitivity and specificity in the diagnosis of HCC. DNASE1L3 combined with AFP has higher sensitivity and can improve the diagnostic efficiency of HBV-related HCC.

Non-linear relationships between children age and pneumococcal vaccine coverage: Important implications for vaccine prevention strategies.

BACKGROUND: Streptococcus pneumoniae (S. pneumoniae) is an important pathogen causing both invasive and non-invasive infections in children, with significant morbidity and mortality worldwide. This study aimed to determine the potential relationships between age and vaccine coverage and between multiple phenotype-genotype characteristics of S. pneumoniae isolated from children. METHODS: All S. pneumoniae isolates were tested for antimicrobial susceptibility, virulence genes, serotypes, and sequence types. The restricted cubic spline models were used to reveal potential relationships between children age and pneumococcal vaccine coverage. RESULTS: For capsular-based vaccines, we observed a high coverage rate of 13-valent pneumococcal conjugate vaccine (PCV13, 85.8%) and a significantly non-linear relationship between children age and vaccine coverage (including PCV7, PCV10, and PCV13), with marked fluctuations in children aged < 2 years. For protein-based and pilus-based vaccine candidates, we demonstrated dynamic non-linear relationships between age and vaccine coverage, maintaining a stable and high coverage rate of ply and lytA for all age groups. Moreover, there were significantly high-dimensional corresponding relationships among multiple phenotype-genotype characteristics of S. pneumoniae isolates (such as ST271 associated with serotype 19F, PI-2, and extensively drug-resistance). CONCLUSIONS: Our findings suggest that the age for high PCV coverage being children aged ≥ 2 years and also provide important evidence for supporting ply and lytA as priority candidate targets for the development of new-generation protein vaccines.

Molecular epidemiology of Streptococcus pneumoniae isolated from pediatric community-acquired pneumonia in pre-conjugate vaccine era in Western China.

BACKGROUND: Streptococcus pneumoniae (S. pneumoniae) is one of the most common pathogens which can cause morbidity and mortality in pediatric infections worldwide. This study aimed to describe the phenotypic and molecular characteristics of community-acquired pneumonia (CAP)-causing S. pneumoniae recovered from children in Western China. METHODS: We retrospectively enrolled pediatric patients younger than 5 years diagnosed with CAP. All 419 S. pneumoniae isolates were tested for antibiotic susceptibility, serotypes, virulence genes, resistance genes, and sequence types. The potential relationships between molecular characteristics were tested by correspondence analysis. RESULTS: Most of S. pneumoniae isolates were resistant to erythromycin, tetracycline, clindamycin and trimethoprim-sulfamethoxazole, with 93.8% isolates classified as multidrug resistant. The dominant STs were ST271 (30.8%) and ST320 (12.2%), while the prevailing serotypes were 19F (46.8%), 6B (11.5%), 23F (9.5%) and 19A (9.3%). The coverage rates of PCV-7 and PCV-13 were 73.03% and 86.16%, while the coverage rates of PCV13 among children aged < 1 year and 1-2 years were high in 93.18% and 93.62%. We also observed that CC271 expressed more of mef (A/E), lytA, rlrA and sipA than non-CC271 isolates. Moreover, there were strong corresponding relationships between molecular characteristics. CONCLUSIONS: The high coverage rate of PCV13 suggests the necessity of introducing the PCV13 vaccine in Western China. Our findings underscore the value of monitoring multiple molecular characteristics to provide new guidance for developing future pneumococcal vaccines.

Clustering of Staphylococcus aureus carriage among kindergarten children in Liuzhou / 中国学校卫生

Objective@#To explore clustering and risk factors of Staphylococcus aureus (S. aureus) carriage among kindergarten children in Liuzhou.@*Methods@#Two sided nasal swabs were collected from 1 702 children in Liuzhou from April to June 2018. Parents of all the children were investigated by questionnaires. The random effect Logistic regression was used to analyze the clustering and risk factors of S. aureus carriage.@*Results@#The carriage rate of S. aureus among kindergarten children was 16.3%. The randomeffect Logistic regression model indicated that the class-level random effect of S. aureus carriage among children was statistically significant(Z=2.12, P<0.01). Children aged 6 to 7 years (OR=2.18, 95%CI=1.45-3.27) and 5 years (OR=1.65, 95%CI=1.08-2.50) had higher carriage rates of S. aureus than those aged 3-4 years. The history of antibiotic using (OR=1.45, 95%CI=1.05-2.01) and skin and soft tissue infections (OR=1.36, 95%CI=1.04-1.79) in the previous year were risk factors of S. aureus carriage among children.@*Conclusion@#The class level clustering of S. aureus carriage is observed in healthy children. Age, history of antibiotic usage and history of skin and soft tissue infections are associated with risk of S. aureus carriage among preschool children.

Phenotypic and Molecular Characteristics of Community-Associated Staphylococcus aureus Infection in Neonates.

BACKGROUND: Staphylococcus aureus is an important human pathogen causing a wide variety of diseases ranging from mild skin infections to life-threatening bacteremia. This study aimed to provide insight into the phenotype-genotype characteristics of S. aureus isolated from neonates. METHODS: A hospital-based retrospective study was conducted to recruit neonatal patients with community-associated S. aureus infection. All 92 S. aureus clinical isolates were tested for antimicrobial susceptibility, resistance genes, virulence genes, and multilocus sequence typing. RESULTS: A total of 92 S. aureus isolates were included in this study, including 29 (31.5%) MRSA isolates. Most S. aureus isolates were susceptible to gentamicin, and most methicillin-resistant S. aureus (MRSA) isolates were susceptible to vancomycin and linezolid. The predominant S. aureus genotypes were CC188 (ST188), CC59 (ST338), CC5 (ST5), CC88 (ST8), and CC6 (ST6), with CC59 (ST338) as the most prevalent MRSA. We observed a significantly corresponding relationship between clonal complexes and resistance patterns (such as CC45/CC59/CC121/CC630 associated with multidrug resistance) or the number of virulence genes (such as CC1/CC5/CC45/CC59/CC88 associated with harboring 5-7 virulence genes, and CC22/CC25/CC121 associated with carrying 8-13 genes). Moreover, both univariate and multivariate analyses indicated that invasive S. aureus isolates were significantly associated with resistance to several classes of antibiotics and carrying specific virulence factors. CONCLUSION: Our findings provide insight into phenotype-genotype characteristics for S. aureus isolates so as to provide new ideas for differentiating potential genetic backgrounds and monitoring new epidemiologic trends.

Serotype distribution and antimicrobial resistance of Streptococcus pneumoniae causing invasive diseases in China: a meta-analysis.

BACKGROUND: To summarize information about invasive pneumococcal disease (IPD) among children in mainland China. METHODS: Sixteen eligible studies were included in this systematic review and the random effect model was used to estimate the pool prevalence of IPD. RESULTS: The most predominant serotypes circulating in children were 19F (27.7, 95% confidence interval (95% CI): 17.7-37.6%), 19A (21.2%, 16.4-26.1%), 14 (16.5%, 12.8-20.1%), 6B (8.6%, 5.2-10.8%) and 23F (7.3%, 5.2-9.5%). The serotype coverage of the available pneumococcal conjugate vaccines PCV7, PCV10, and PCV13 was 60.8% (52.5-69.4%), 65.1% (57.7-72.4%), and 90.0% (87.1-92.8%), respectively. The pooled antibiotic resistance rates of Streptococcus pneumoniae revealed a resistance to penicillin prevalence rate of 32.0% (12.1-51.9%). Approximately 94.4% (90.7-98.1%) and 92.3% (87.4-97.3%) of isolates were resistant to erythromycin and clindamycin. eBURST analysis revealed great diversity among isolates, with 102 sequence types (STs) for 365 isolates. The major predominant clonal complexes (CCs) were CC271 (43.6%, 159/365), CC876 (13.4%, 49/365), CC81 (5.2%, 19/365), and CC90 (4.1%, 15/365). Long-term and regional surveillance of S. pneumoniae is necessary. CONCLUSIONS: Based on our pooled results showing that PCV13 coverage of the reported serotypes was 90% and that most serotypes contributed to the distribution of antibiotic-resistant isolates, implementation of PCV13 into the Chinese Expanded Program on Immunizations (EPI) would achieve health benefits in Chinese children.

Interactions between genetic variants involved in the folate metabolic pathway and serum lipid, homocysteine levels on the risk of recurrent spontaneous abortion.

BACKGROUND: The interaction between folate pathway gene polymorphisms and homocysteine, serum lipid leverls are poorly understood in patients with recurrent spontaneous abortion (RSA). The aim of this study is to explore the effects of folate pathway gene polymorphisms (the 5-10-methylenetetrahydrofolate reductase, MTHTR C677T, MTHFR A1298C and the methionine synthase reductase, MTRR A66G) and their interactions with homocysteine on serum lipid levels in patients with RSA. METHODS: A total of 403 RSA women and 342 healthy women were randomly selected. Genotyping of the MTHFR C677T, A1298C and MTRR A66G were performed by TaqMan-MGB technique. Serum homocysteine, folate, fasting glucose, fasting insulin, Interleukin 6, Tumor necrosis factorα (TNFα) and lipid profiles were measured according to the kits. Continuous variables were analyzed using 2-sample t-tests. Categorical variables were analyzed and compared by χ2 or Fisher's exact tests. Unconditional logistic regression model was applied to test the interactions of gene polymorphisms on RSA. RESULTS: The distribution of genotype of CC, CT TT and T allele of MTHFR C677T, genotype of AA and C allele of MTHFR A1298C, and genotype of AA, AG and G allele of MTRR A66G were different between cases and controls (all p were < 0.05). There were significant interactions between MTHFR C677T-A1298C and MTHFR A1298C-MTRR A66G in RSA group and control group, with ORs of 1.62 (95%CI: 1.28-2.04, p < 0.001) and 1.55 (95%CI: 1.27-1.88, p < 0.001), respectively. Serum TNFα level and insulin resistant status (HOMR-IR) were higher in RSA group than in control group (p = 0.038, 0.001, respectively). All the three gene SNPs except MTRR 66AG gene variant had detrimental effects on HOMA-IR (all p were < 0.05). RSA group who carried the MTHFR 677CT, TT, CT/TT genotypes and MTRR 66AG, AG/GG genotypes had detrimental effects on serum homocysteine levels, the MTHFR 677CT, CT/TT genotype carriers had favorable effects on serum folate levels, the MTHFR 677TT, CT/TT, 1298 AC, AC/CC genotype carriers had detrimental effects on serum low-density lipoprotein cholesterol (LDL-C) levels, and the MTRR 66AG genotype carriers had lower high-density lipoprotein cholesterol (HDL-C) levels than the AA genotype carriers (all p were < 0.05). CONCLUSIONS: Interaction between the MTHFR C677T, A1298C and MTHFR A1298C, MTRR A66G are observed in our RSA group. Besides, all the three gene SNPs except MTRR 66AG gene variant had detrimental effects on HOMA-IR. MTHFR C677T and MTRR A66G gene variants had detrimental effects on serum homocysteine levels and insulin resistance status, while MTHFR C677T, A1298C and MTRR A66G gene variants had detrimental effects on certain serum lipid profiles.

Pulmonary Function Testing in Pediatric Pneumonia Patients With Wheezing Younger Than 3 Years of Age.

Background. Wheezing symptoms are one of the risk factors in young pneumonia patients that often leads to asthma development. Infant pulmonary function test (iPFT) is potentially a useful tool to help identify and manage these high-risk pneumonia patients. Methods. To examine whether patients with wheezing symptoms are more likely to have poorer pulmonary function and treatment outcomes, and also to explore the clinical benefit of iPFT in young pneumonia patients, we conducted a retrospective analysis of 1005 pneumonia inpatients <3 years of age who had undergone iPFT testing in 2016 at Liuzhou Maternity and Child Healthcare Hospital in Guang-Xi, China. Results. We identified from the hospital database 505 pneumonia patients who presented with wheezing and 500 without wheezing. Univariate analysis showed that wheezing symptoms, viral infection, age <1 year, female gender, and prematurity were significantly associated with poorer iPFT results. After adjusting for confounders, patients with wheezing showed significantly poorer pulmonary function. Patients with wheezing had longer length of stay (7.9 ± 3.9 days vs 6.5 ± 2.6 days; P < .001) and lower percent with no residual clinical symptoms at discharge (58% vs 98%; P < .001) when compared with those of non-wheezing patients. In addition, 81% of patients with viral infection as compared with 43% of patients with nonviral infection presented with wheezing symptoms (P < .001). Conclusion. Wheezing symptoms were associated with poorer iPFT measures and treatment outcomes for pneumonia inpatients <3 years of age. Patients with wheezing had poorer treatment outcomes. iPFT can be useful in assessing and monitoring young patients with high risk of developing asthma or chronic lung disease later in life.

Etiology of acute otitis media and phenotypic-molecular characterization of Streptococcus pneumoniae isolated from children in Liuzhou, China.

BACKGROUND: The etiology and epidemiology of acute otitis media (AOM) are poorly understood in China. This study aimed to describe the etiology of AOM and the phenotypic and molecular characteristics of AOM-causing Streptococcus pneumoniae (S.pneumoniae) recovered from Chinese children. METHODS: A retrospective study was conducted to enrol patients younger than 18 years diagnosed as AOM. Middle ear fluid specimens were collected then cultured for bacterial pathogens. All S.pneumoniae isolates were tested for antibiotic susceptibility, serotypes, virulence genes, antibiotic resistant determinants and sequence types. RESULTS: The dominant otopathogen among AOM children was S.pneumoniae (54.4%). Among S.pneumoniae isolates, there were 97.3, 97.3 and 75.7% isolates resistant to erythromycin, tetracycline and trimethoprim-sulfamethoxazole, respectively. There was 72.8% S.pneumoniae with multidrug resistance. The dominant sequence types (STs) were ST271 and ST320, whereas the prevailing serotypes were 19F and 19A. The 7-valent and 13-valent pneumococcal conjugate vaccine (PCV) coverage among AOM children were 73.0 and 94.6%, respectively. Additionally, we found that CC271 expressed more of mef(A/E) (P < 0.001), pspA (P = 0.022) and sipA (P < 0.001) than non-CC271 isolates. CONCLUSION: The high prevalence of international multidrug-resistant clone (Taiwan19F-14) in China necessitates continued dedication to expand PCV13 immunization and better control of antibiotic use in China.

Molecular characterization and antimicrobial susceptibility of Staphylococcus aureus isolated from children with acute otitis media in Liuzhou, China.

BACKGROUND: There have been few studies focused on the prevalence, bacterial etiology, antibiotic resistance, and genetic background of Staphylococcus aureus (S. aureus) in children with acute otitis media (AOM) in China. METHODS: A retrospective study was conducted in Liuzhou Maternity and Child Healthcare Hospital. Patients younger than 18 years diagnosed with AOM were enrolled in the study. Middle ear fluid specimens were collected and cultured for bacterial pathogens. The antibiotic susceptibility, virulence genes, macrolide resistant genes and sequence types of S. aureus were identified. RESULTS: From January 1, 2013 to December 31, 2015, a total of 228 cases of AOM were identified. Pathogenic bacteria were positive in 181 (79.4%) of 228 specimens. Streptococcus pneumoniae was the most common bacteria (36.4%), followed by S. aureus (16.2%). Among the 37 S. aureus isolates, 12 (23.5%) were methicillin-resistant S. aureus (MRSA), and 25 (77.5%) were methicillin-susceptible S. aureus (MSSA). A total of 23 isolates (62.2%) were resistant to erythromycin, 40.5% of isolates were resistant to clindamycin, and 37.8% isolates were resistant to tetracycline. Twenty-three isolates were multi-drug resistant (MDR) S. aureus. Eighteen isolates carried the pvl gene. Up to 22 (59.4%) isolates expressed ermA gene, 8 (21.6%) isolates expressed both ermA and ermC genes, and only 8.1% expressed ermB. Among all S.aureus isolates, 7 sequence types (STs) were identified by multilocus sequence typing (MLST). The most common ST was ST59 (16/37, 43.2%), followed by ST45 (7/37, 18.9%) and ST30 (7/37, 18.9%). The predominant MSSA isolates were ST59-t437-MSSA (5/25, 20.0%), the prevailing MRSA isolates were Taiwan related strains ST59-SCCmec-IVa/V (5/12, 41.6%). CONCLUSIONS: S. aureus was the second most common cause for AOM in children in Liuzhou. Most of the S. aureus was MDR which carried a high proportion of ermA and ermC gene. CA-MRSA (ST59-SCCmec-IV/V-t437) is circulating in children with AOM. These findings support continued surveillance of S. aureus infections in children with AOM in both communities and hospitals.

Persistent candidemia in very low birth weight neonates: risk factors and clinical significance.

BACKGROUND: The prevalence and risk factors for persistent candidemia among very low birth weight infants are poorly understood. This study aimed to investigate the epidemiology of persistent candidemia over a 4-year period in a neonatal intensive care unit (NICU) in Liuzhou, China. METHODS: We retrospectively extracted demographic data, risk factors, microbiological results and outcomes of very low birth weight infants with candidemia in our hospital between January 2012 and November 2015. Persistent candidemia was defined as a positive blood culture for > 5 days. Logistic regression was used to identify risk factors associated with persistent candidemia. RESULTS: Of 48 neonates with candidemia, 28 had persistent candidemia. Both mechanical ventilation and intubation were significantly associated with increased rates of persistent candidemia (P = 0.044 and 0.004, respectively). The case fatality rate for the persistent candidemia group was 14.3%. CONCLUSION: The rate of persistent candidemia was high among very low birth weight neonates. Mechanical ventilation and intubation were the major factors associated with the development of persistent candidemia. This study highlights the importance of intensive prevention and effective treatment among neonates with persistent candidemia.

Group B streptococcal colonization in mothers and infants in western China: prevalences and risk factors.

BACKGROUND: The epidemiology of maternal and infant Group B streptococcus (GBS) colonization is poorly understood in China. The aim of this study is to explore the prevalence and risk factors associated with maternal and infant GBS colonization in Western China. METHODS: From January 2017 to June 2017, a prospective study was conducted to estimate the maternal and infant GBS colonization rate by maternal rectovaginal and infant nasopharynx, ear canal and umbilical swab culture. Patient demographics, clinical characteristics and outcomes were collected. Chi-square and logistic regression analyses were used to examine the risk factors associated with GBS colonization of mothers and infants. RESULTS: The GBS colonization rate in mothers and infants was 6.1 and 0.7%, respectively. The vertical transmission rate was 7.6%. The early onset GBS infection rate was 0.58 per 1000 live births and mortality was 0.29 per 1000 live births. Age younger than 40 years (p = 0.040) and minority ethnic status (p = 0.049) were associated with higher GBS colonization rate in pregnant women. Positive GBS status in the mother prior to delivery (p < 0.001) as well as longer duration of membrane rupture (≥12 h) (p < 0.001) and longer labor (≥4 h) (p < 0.001) were all significant risk factors for GBS colonization in infants. Compared to infants without GBS colonization, infants colonized with GBS were more likely to have had a temperature of ≥38 °C (p < 0.001), developed early onset infection (EOD) (p < 0.001), and been prescribed antibiotics (p < 0.001). Furthermore, infants with GBS were more likely to have been admitted to neonatal intensive unit (NICU) (p < 0.001) with a longer hospital length of stay (LOS) (p < 0.001). CONCLUSIONS: Maternal GBS colonization, longer duration of membrane rupture and labor were all major risk factors associated with GBS colonization in Chinese infants. Infant GBS colonization was associated with increased risk of EOD and NICU admission as well as longer LOS.

Maternal vitamin D deficiency increases the risk of adverse neonatal outcomes in the Chinese population: A prospective cohort study.

BACKGROUND: Although vitamin D (vitD) deficiency is a common problem in pregnant women, in China, few studies have focused on the relationship between maternal vitD deficiency throughout the three trimesters and subsequent neonatal outcomes in China. METHODS: Between 2015 and 2016, maternal serum and neonate cord blood samples were collected from 1978 mother-neonate pairs from Liuzhou city. RESULTS: The mean concentrations of 25-hydroxy vitD (25(OH)D) were 16.17±6.27 and 15.23±5.43 ng/ml in the mother and neonate groups, respectively, and the prevalence values of vitD deficiency in the two groups were 78.18% and 83.27%, respectively. Logistic regression showed that maternal vitD deficiency independently increased the risk of gestational diabetes mellitus (GDM) (adjust OR, aOR 1.08; P = 0.026). A relatively lower risk of vitD deficiency was observed in the third trimester than in the first and second trimester (aOR 0.80; P = 0.004). VitD-calcium cosupplementation during pregnancy improves the vitD deficiency in both the maternal and neonatal groups (aOR 0.56, 0.66; P<0.001 and 0.021, respectively). Maternal vitD deficiency significantly increased the risk of neonatal low birth weight (LBW) (aOR 2.83; P = 0.005) and small-for-gestational-age (SGA) (aOR 1.17; P = 0.015). There was a positive correlation between maternal and neonatal vitD deficiency (r = 0.879, P<0.001). VitD supplementation during pregnancy significantly reduced the risk of giving birth to LBW infants (OR = 0.47, 95%CI = 0.33-0.68, P<0.001). CONCLUSIONS: Further research focusing on the consumption of vitD with calcium during pregnancy and the consequential clinical outcomes in Chinese pregnant women is warranted.

Phenotypic and molecular characterization of Streptococcus pneumoniae in pre-conjugate vaccine era: A Chinese hospital-based retrospective study.

BACKGROUND: Streptococcus pneumoniae (S. pneumoniae) is an important pathogen in causing global morbidity and mortality among children. This study aimed to determine phenotypic and molecular characteristics of S. pneumoniae causing infections in children under five years in China. METHODS: A hospital-based retrospective study was conducted. All 537 S. pneumoniae isolates were tested for antimicrobial susceptibility by E-test method, molecular characteristics including resistance genes, virulence genes and serotypes by multiplex polymerase chain reaction (PCR) method, and sequence types (STs) by sequencing seven housekeeping genes. Minimum spanning tree and correspondence analysis were used to reveal the potential relationship between serotypes and STs. RESULTS: Most of S. pneumoniae isolates were resistant to erythromycin (93.9%) and tetracycline (86.4%), with the predominant resistance genes being erm(B) (92.6%) and tet(M) (95.5%). The prevalent serotypes were 19F, 6B, 19A, 23F and 14, the coverage rate of PCV13 was high in 85.8%, and the predominant STs were ST271, ST320, ST3173, ST81 and ST876. A significant correlation existed between STs and serotypes, with ST271/19F and ST320/19A as the most prevalent clones. Notably, ST271/19F and ST320/19A isolates were associated with resistance to specific antibiotics and carrying of mef(A/E), rlrA and sipA genes. CONCLUSIONS: Our findings suggest the introduction of PCV13 vaccine to Chinese children, and underscore the value of monitoring multiple characteristics to detect new epidemiologic trends and provide implications for the formulation of multivalent pneumococcal vaccines.